The object of Brazilian Pat. No. 7500262, of the same applicant, comprises a refining assembly for wood pulp or the like, the principal feature of which consists in the fact that the triturating work of the vegetable mass is done by the action of a coaxial assembly of three refining discs, of which the extremes are statically and respectively mounted on the cover and on an axially adjustable support inside the body of the unit, thus providing stator discs, the intermediate one, or rotor disc, being mounted on the hub of the control axle-shaft.
Further in regard to the refining discs, the first stator disc is provided with a centrally located opening surrounding the axle-shaft and fed directly by the vegetable pulp which enters the unit, the rotor disc being formed by a single, compact body, with a double refining surface, as well as provided with a central, multilobe opening, for material to pass, said rotor disc being integrally mounted on the axle-shaft hub, by means of internal radial lugs, projecting from the lobe formations on the central opening thereof and attachable to correspondingly radial and external fins provided on the referenced hub.
Notwithstanding all the positive characterization of the pulp-refining assembly of the above-mentioned patent, with a highly efficient job being performed by the coaxial assembly of the three refining discs provided therein, some improvements can still be presented, particularly in connection with the rotor disc, and principally as regards to the constructive characteristics thereof.
As a matter of fact, the cited rotor disc, such as set forth in the aforementioned patent, and on account of being comprised by a single and compact body, is subject to a certain amount of criticism related to a relatively high weight, as well as to an exaggerated use of material in the fabrication thereof and, further, to the fact that it requires a weld coat between the blades, the same being said as regards to the mounting hub thereof, which is also relatively heavy and with the internal lobe formations somewhat restricting a greater passage of mass.